Polyhydroxyamino acid compounds



Patented Mar. 23, 1954 POLYHYDROXYAMINO ACID COMPOUNDS Frederick C. Bersworth, Framingham Center, and Albert E. Frost, Marlborough, Mass.; said Frost assignor to said Bersworth No Drawing. Application June 11, 1952, Serial No. 292,996

6 Claims. 1

This invention relates to a new and useful class of polyhydroxyamino acid compounds which are sequestering agents for metal ions, including iron, in strongly acid to strongly alkaline solution.

It is, therefore, an object of this invention to prepare polyhydroxyamino acids which are capable of holding metal ions, particularly ferric ions, in solution over a wide pH range.

Another object of this invention is to provide compounds useful as intermediates in the production of soap-like products.

These and other objects of this invention are accomplished by the following invention which comprises polyhydroxyamino acids of the general formula:

HOOH2-CH2 OH OH alkyl acid, such as chloropropionic acid, on a suitable polyhydroxyl polyamine, such as, N,N- di-(2-hydroxy-3-iminodiethanol-propyl) ethylene diamine, is not a satisfactory method. be-

5 cause of the formation of ether type acids along with the desired polyhydroxyamino acids.

The compounds of this invention wherein A represents -CH2COOH and its alkali metal salts are best prepared by the process set forth by Bersworth in U. S. Patent 2,407,645, issued September 17, 1946. This method, briefly, consists in adding two mols of formaldehyde and two mols of sodium cyanide slowly and in small balanced quantities under strongly alkaline conditions to the proper polyhydroxyl polyamine, such as N,N-

CHe-CHcOH wherein Y is a bivalent alkylene radical of two to three carbon atoms which may be unsubstituted or may bear one or more alkyl groups of one to two carbon atoms; n is a positive integer and is selected from the group consisting of 1, 2, 3 and 4; A is a member of the group consisting of -CH2COOH, CH2CH2COOH, -CI-I2PO3H, -CH2CH2PO3H, -CH2CH2SO3H and their alkali metal salts.

The compounds of this invention may be pre pared by any of several known methods. One of these methods which is applicable to the synthesis of all the compounds of this invention comprises reacting two molecular proportions of a suitable w-halogen substituted C-alkyl substituted triethanolamine, such as C- (2-chlor0- methyD-triethanolamine, with one molecular proportion of the appropriate alkylene diamine bearing the desired substituents A and Y under conditions so as to obtain a maximum yield of the desired product.

A second method of preparation consists in reacting an appropriate w-amino-C-alkyl-substituted triethanolamine derivative, for example, C-(Z-amino-methyl)-triethanolamine, with the proper alkylene dihalide, such as, N,N'-di-(2- chloro-ethyl)-ethy1ene-diamine diacetic acid in a two to one molar ratio.

The preparation of the polyhydroxyamino acids of this invention by the action of a. halogen di- (2-hydroxy-3-iminodiethano1 propyl) -isopropylene diamine, and heating and agitating the mixture.

be prepared by methods other than those described above and also by modifications which will appear to those skilled in the art, w prefer to use the procedures followed in the specific ex amples since they are easily carried out, require no complicated apparatus and involve a mini- As symmetrical alkylene diamino acids suitable for use in making the new compounds there may be mentioned: ethylene diamine-N,N'-diacetic acid, ethylene *diamine-N,N'-dipropionic acid, isopropylene diamine-N,N-diacetic acid, 50 isopropylene diamine-N,N'-dipropionic acid, tri- Although the compounds of this invention can methylene diamine-N,N'-diacetic acid, trimethylene diamineN,N'-dipropionic acid, ethylene diamine-N,N'-dimethyl phosphonic acid, isopropylene diamine-N,N-dimethyl-phosphonic acid, trimethylene diamineN,N'-dimethyl phosphonic acid, ethylene diamine-N,N-diethyl phosphonic acid, isopropylene diamine-N,N-diethyl phosphonic acid, trimethylene diamine-N,N'-diethyl phosphonic acid, ethylene diamine-N,N'-diethyl sulfonic acid, isopropylene diamine-N,N'-diethyl sulfonic acid, trimethylene diamine.-N,N-diethyl sulfonic acid and their alkali metal salts.

The following w-halogen-substituted-C-alkylsubstituted triethanolamines may be mentioned: as suitable starting materials, namely, C.-(2- chloromethyl) triethanolamine; C-(Z-chloroethyl) -triethanolamine, C-( 2-chloropropyl) -triethanolamine, C-(2-chlorobutyl) '--triethano1a mine, C-(Z-bromomethyl)-triethanolamine and. C- (2-bromopropyl) -triethanolamine.

As suitable N,N-di-(hydroxy-w-iminodiethanol-alkyl) -alkylene diamines there may be mentioned, for example, N,N-di-(2-hydroxy-3-iminodiethanol-propyl)-ethy1ene diamine, N,N'-di- (2-hydroxy3 iminodiethanol-propyl) isopropyl'- ene diamine, N,-N -di- (2.-hydroXy-3-iminodiethanol-propyl) -trimethylene diamine, N,N'-di- 3- hydroxy-4-iminodiethanol-buty1) ethylene diamine, N,N' -di- (4-hydroxy- 5' iminodiethano-lpentyl) -ethylene diamine, N,N' -di- (5-hydroxy- G iminodiethanol-hexyl) -isopropylenev diamine and N,N'-di-(B-hydroxy-4-iminodiethanol-butyl') -trimethylene diamine.

In addition to the symmetrical alkylene diaminov acids mentioned above; 1,2-'diamino-cyc1ohexane-N,N'-dia1ky1 carboxylic; phosphonic and sulfonic acids and their alkali metal salts may be used.

A preferred compound of this series is pro+ duced from l,2-diaminocyelohexane-N,N'-diacetic acid and C-(2-chloromethyl)-triethanolamine and is represented by the following formula:

COOH' COOH The. above. starting materials are mentioned only forpurposesof illustrationand not for limitation oftheinvention. Obviously other mem bers. of' the classes indicatedby the definitions treated with sodium cyanide and formaldehyde according to the process set forth by Bersworth in U. S. Patent No. 2,407,645, issued September 17, 1946. The resulting yellow-orange solution sequestered metal ions, including iron, in strongly acid to strongly alkaline solution. Evaporation of the solution to dryness under reduced pressure gave a semi-crystalline yellow liquid which is the disodium salt of N,N-di-(2-hydroxy-3-iminodiethanol-propyl) -ethylene diamine N ,N'-diacetic acid" having the following formula:

C Hz-C Hz 0 H O H O H C 112-0112 0 H N-CH2C Z H-C Hs-N-C Hz-CHz-N-C H24 1 H-O HTI T CHT'C HzOH CH2 lHz CH2-CH2OH C O O Na 3 O O Na EXAMPLE II CHz-CH2OH EXAMPLE III To 0.1 mol (26.2 g.) of the disodium salt'of N,N-trimethylene' diamine dipropionic acid in 100 m1. of water heated to gentle reflux, there:was=- added dropwise over a two hour period, 0.2 mol (45.2 .g.) of. C-(2-chloropropyl). -triethanolamine in 150ml. ofwater'. The reaction mixture was. then heated for an additional fourhours after. which'it wasevaporated to dryness under reduced pressure and the dry residue extracted repeatedly with boilingmethanolh Evaporation of the'methanol solution to dryness gave an extremely viscid yellow liquid which is N,N.'-die(4=hydroxy -5- iminodiethanol-pentyl) trimethylene diamine- N,N-dipropionic acid having. the formula:

EXAMPLE Iv 0.2 mol (7019" g.) of'N,N':-di(2-hydroxy 3 iminodiethanol-propyl)-ethy1ene diamine was- To 0.'1' mol- (2714 g.) of "ethylenediamine-N,N-

diethyl phosphonic acid in 200' ml. of water con taining 0.2 mol (8.0' g.) of sodium-hydroxide and heated to reflux, there was added over a two hour period, a solution of 0.2 mol' (7911 g.) of C- (2'-' chloromethyl)-triethanolamine in 250' ml. of After refluxing for" an additional four" water. hours, the mixture was workedupas in Eizample 'IlIto give aviscid yellowliquid" which." is N,N--

6 di- (Z-hydroxy-3 iminodiethanol-propyl)- ethyllowed by alcoholic extraction of the dry residue ene diamine-N,N-diethyl phosphonic acid havand evaporation of the alcoholic solution. The: ing the formula: products vary from yellow viscid oils to yellow semicrystalline liquids. cur-onion l 5 The insolubility of ferric hydroxide and some OH OH CHPCHNH basic salts of the ferric ion is well known. Aqueous solutions of ferrous compounds are rapidly T oxidized to insoluble ferric compounds in acid 0112-0132013 CH2 om CHZ'CHIOH solutions and, particularly in alkaline solutions.

10 Triethanolamine and certain sugars can seques- I ter iron in alkaline solutions. However, they all Pom Pom suffer the disadvantage of being applicable only in alkaline medium; the sugars suffer the fur- Its aqueous solutions sequester metal ions includther disadvantage of decomposition in alkali, ing iron in strongly acid to strongly alkaline soluparticularly on warming. The polyhydroxyation. mino acids of this invention are stable in acid E PLE V and in alkaline solution and possess a high sol vent action on ferric hydroxide even in strongly alkaline medium.

02 m of 'O G lID-tfl- The compounds of this invention possess the ethanolamine in 200 ml. of water was added ability to hold a very high concentration of metal dropwise with good stirring and over a two hour ions in solution because of the high proportion period to a slowly refluxing solution of 0.1 mol of chelating centers in the molecule. For exam- (27.6 g.) of ethylene diamine-N,N'-diethyl sulple, the two triethanolamine groups in the molefonic acid in 15 ml. of water containing 0.2 mol 2 cule present two quadridentate groups for chela- (8.0 g.) of sodium hydroxide. After four hours tion and the two amino acid groups present two of refluxing, the mixture was worked up as in Exbidentate groups for chelation. As a result, comample III to give a pale yellow semi-crystalline plex compounds of the type illustrated below may product which is N,N'-di-(2-hydroxy-3-iminoform:

0 CH(CH2),.-N--Y--N(OHz),.-CH o l I 1 H20 (3112 ICH2 /M\ $112 I H2 /OH2 HzO Fe N o=o-0 oo=o N--Fe-OH:

CHz---CH2 CH2Cn diethanol-propyl) -ethy1ene diamine-N,N-diethyl wherein the terms 11., and Y have the same signifisulfonic acid having the formula: canoe as above.

GHQ-onion 40 Having hereinabove disclosed the present in- OH OH OHM: HEOH vention generically and specifically and having given a plurality of specific embodiments of the l I NGH2-CHC 2- -C 2- T same, it is believed apparent that the invention cHi-oHloH CH2 CH2 am-onion may be widely modified without essential depar- (IJHZ (IJHZ ture therefrom and all such modifications and A departures are contemplated as may fall within 0:11 503E the scope of the following claims. Its aqueous solutions sequester metal ions over What we claim awide pH range. 1. Chemical compounds corresponding to the It is quite likely that these products which are f l reported as viscid oils or semi-crystalline liquids CHFCHZOH may eventually become crystalline. The physical state of these products is, therefore, not to OH CHICH'OH be taken as definitely established and the claims f r0 -(CH:)-N-YI I-(CHm-CH-Glih-N are not limited to substances with the exact prop- OHHHOH A A CHPOHIOH erties reported.

wherein Y is a bivalent alkylene radical of two to three carbon atoms selected from the group consisting of unsubstituted and substituted alkylene radicals carrying at least one alkyl group of from 1 to 2 carbon atoms; n is a positive integer and is selected from the group consisting of 1, 2, 3 and 4 and A is a member of the group consisting of -CH2COOH, CH2CH2COOH, CH2P03H, -CH2CH2PO3H, -CH2CH2SO3H and their alkali metal salts.

2. The compound N,N'-di-(2-hydroxy-3-iminodiethanol propyD-ethylene diamine-N,N'-diacetic acid conforming to the formula:

CHz-CHrOH The products of this invention possess useful and interesting properties as sequestering agents for metal ions, and especially for iron, in strongly acid to strongly alkaline solutions and even dissolve ferric hydroxide in strongly alkaline solutions at room temperature.

They, therefore, have application in the textile and leather industries, in cosmetic and soap compositions, in washing compounds, soaker alkali, glass and metal cleaning preparations, in electroplating, as antioxidants, additives to lubricants and in numerous other applications for which sequestering agents are commonly employed.

The compounds of this invention need not be isolated from their aqueous reaction mixtures but 7 OH CRT-onion can be used as such in most applications. The N-CHa-GH-OH2-N-OH;CH -NCH JJEL-(JH N aqueous solutions of these products vary from a CHrOHOH CH2 (IJH2 HrCHwOH yellow to an orange color. The products may be isolated from their aqueous solutions by evapora- (3003 000K tion of the neutralized solutions to dryness fol- 3. The compound N,N'-di-(2-hydroxy-3-iminomevagzw diethano1.propy1) '-isoprop&1ene :diamine-Nmhdiacetic avoid conforming :to *the formula; :1

1 4;. The compound N-,N' -di- (4-hydroxy-5-imin'o diethanol-pentyl) '-trimethy1ene diamine-N,N'*-dipropionio acid mzonforming to the formula cHkcHzoH' 8Z1 yl xsulfoniciacidiconforming: touthe formula. :"V

CHi-OHzOH ('i)H $11 CHz-CHzOH 5 N--CH:-C11--CHar-N-CHrCHa-N-CHz-CIEI-CHr-ISF CHir-GHiOH CHL CH: CHr-CHiOH H: Hi AOQH 03H FREDERICK C. BERSWORTH. ALBERT E. FRGST-l CHi-CHzOH.

. 5'1 Theucompound N,N'-di- (2-hydroxyr3riminodiethanol-propyl) -ethy1ene diamine-N,N -dieth yI-phosphonic acid conforming to the formula? orb-0111011 OH- OH N 0Era-oH-om-N-oHZ-CHZ-N-CHTcH-Cm-I I CHa-(JHgOH. (Illa-CH1v CHa-CHz V CHz-CH2OH P.O;H P 03H 6. The compound N,N-d.i-(Z-hydroxy-B-iminm diethanol-propyl)-ethy1ene diamine-N,N-dieth- Referencesucited in the file: of 'thisu'patent; UNITED'STATES PATENTS 

1. CHEMICAL COMPOUNDS CORRESPONDING TO THE FORMULA: 